1. Field of the Invention
This invention relates to electrically conductive compositions which are cured by active rays of light such as ultraviolet rays and visible rays, and more particularly to electrically conductive compositions containing electrically conductive polyanilines.
Electrically conductive polymers are being practically applied as electronic devices making use of the property as semiconductor, electrochromic materials utilizing the changes of absorption wavelength at the time of oxidation or reduction, battery electrode materials, electrochemical action substances, electrically conductive fillers for antistatic and electromagnetic wave shielding materials, etc.
In particular, electrically conductive polymers such as polythiophene, polypyrrole, and polyaniline are stable in the air, and those with the electrical conductivity of 100 S/cm or more are electrically conductive polymers suited to practical use.
2. Description of the Prior Art
These electrically conductive polymers are treated by doping for forming a complex of a dopant and an electrically conductive polymer in order to provide them with a metallic electrical conductivity. As this treatment, in such electrically conductive polymers as polypyrrole and polythiophene, it is relatively easy to dope by using iodine or arsenic pentafluoride as the dopant.
In this method, however, as the dopant is released from the electrically conductive polymer with the lapse of time, and the electrical conductivity is lowered. Besides, polypyrrole or polythiophene darkened in color, and transparent electrically conductive layer is not obtained.
Other methods of providing the electrically conductive polymers with metallic electrical conductivity include a method of doping with anions by an electrochemical technique. In this method, although the electrical conductivity is relatively stable, the treating process is complicated, and it is not suited to mass production.
Known polyaniline electrically conductive materials include the following.
The U.S. Pat. No. 4,983,322 discloses an electrically conductive material comprising polyaniline with a molecular weight of 15,000 or more obtained by polymerization of aniline or its derivatives, an inorganic oxidizing dopant for forming a complex therewith, and a solvent.
The WO 89/01694 discloses a thermally stable, electrically conductive, doped polyaniline comprising an ionized polyaniline obtained by polymerization of aniline or its derivatives, and a dispersant organic dopant possessing SO.sub.3.sup.- anion.
The WO 90/10297 also discloses a thermally stable, electrically conductive, doped polyaniline comprising an ionized polyaniline obtained by polymerization of aniline or its derivatives and an organic dopant possessing an anion such as PO.sub.3.sup.-, PO.sub.2.sup.-, PO.sub.3 H.sup.-, SO.sub.2.sup.-, SO.sub.3.sup.-, and COO.sup.-.
Electrically conductive materials including polyanilines show a stable electrical conductivity by the use of inorganic or organic protic acid as dopant, but since this polymer is insoluble in solvents, and processability is inferior when manufacturing a paint.
On the other hand, as the electrically conductive material for providing the synthetic resins and others with electrical conductivity, for example, carbon powder or metal powder, carbon fiber or metal fiber, and others are widely used.
The synthetic resin form is provided with electrical conductivity by dispersing these electrically conductive materials in binder to prepare a coating material, and applying the coating material on a form, or kneading and forming the electrically conductive material in synthetic resin.
The synthetic resin form thus provided with electrical conductivity is used in containers of semiconductor wafer electronic and electric materials, floor and wall materials of semiconductor manufacturing shop, and others that require antistatic performance.
The formed body using such electrically conductive material is generally opaque, and the content cannot be seen through from outside.
To obtain a transparent paint, for example, the Japanese Laid-open Patent Sho. 57-85866 discloses a paint having electrically conductive fine powder mainly composed of tin oxide contained in the binder. This paint forms a transparent and antistatic coat film, but since the binder is a thermoplastic resin, the obtained coat film is generally low in hardness, and insufficient in resistance to solvent.
The Japanese Laid-open Patent Sho. 60-60166 proposes a paint which is cured by ultraviolet ray or visible ray in order to improve the hardness and resistance to solvent.
This paint is excellent in electrical conductivity and transparency, but since fine powder of tin oxide is contained, the hardness and abrasion resistance of the coat film are not enough, and moreover it takes a long time in dispersing the fine powder in the binder, and even after dispersing, because of aggregation, the storage life of the paint is poor.